In 2017 GM began modernizing and hardening their controllers’ security negotiations which is now far more complex and virtually impossible to automate within the EFILive software. That means the end user must now concern themselves with the security negotiations prior to reading or flashing one of these new controllers. Specifically the end user must provide the response (the key) to the controller’s challenge (the seed).

The seed and key are managed by EFILive software inside controller authorization codes or auth-codes. A controller auth-code is a 24 character code split into 6 x 4-character sections.

Automated auth-code processing occurs within approximately 20 minutes of correct order placement.